A quick look in the google.groups archives produced this informative post regarding CCleaner
Can CCLEANER help keep this system running well? - microsoft.public.windows.vista.general | Google Groups
Cleaning the temp internet files and cookies is a reasonable check to your problem.
I'd do a number of tracert and ping -t from a Command Prompt to a number of sites that aren't loading properly.
Right now when I tracert Shaw Communications Inc. ? Digital Phone, Cable & High-Speed Internet it stalls at a Calgary router and never completes. My internet speed is POOR atm and mail through Shaw chokes when sending small attachments w. emails.
eg
C:\Documents and Settings\Ross>tracert www.shaw.ca
Tracing route to www.shaw.ca [204.209.208.8]
over a maximum of 30 hops:
1 10 ms 9 ms 11 ms 70.76.132.1
2 11 ms 11 ms 12 ms rc2nr-ge2-3-1.wp.shawcable.net [24.244.8.194]
3 30 ms 51 ms 27 ms rc1so-pos4-0-0.cg.shawcable.net [66.163.76.193]
4 30 ms 39 ms 28 ms rd1so-ge6-0.cg.shawcable.net [66.163.71.130]
5 36 ms 27 ms 35 ms rd1no-ge4-0-0.cg.shawcable.net [66.163.73.101]
6 * * * Request timed out.
7 * * * Request timed out.
8 * * * Request timed out.
9 * * * Request timed out.
10 * * * Request timed out.
11 * * * Request timed out.
12 * * * Request timed out.
13 * * * Request timed out.
14 * * * Request timed out.
15 * * * Request timed out.
[...]
30 * * * Request timed out.
************************************************** *
C:\Documents and Settings\Ross>ping 66.163.73.101
Pinging 66.163.73.101 with 32 bytes of data:
Reply from 66.163.73.101: bytes=32 time=42ms TTL=251
Reply from 66.163.73.101: bytes=32 time=42ms TTL=251
Request timed out.
Reply from 66.163.73.101: bytes=32 time=30ms TTL=251
Ping statistics for 66.163.73.101:
Packets: Sent = 4, Received = 3, Lost = 1 (25% loss),
Approximate round trip times in milli-seconds:
Minimum = 30ms, Maximum = 42ms, Average = 38ms
************************************************** ***
C:\Documents and Settings\Ross>ping 66.163.73.101 -t
Pinging 66.163.73.101 with 32 bytes of data:
Reply from 66.163.73.101: bytes=32 time=30ms TTL=251
Reply from 66.163.73.101: bytes=32 time=29ms TTL=251
Reply from 66.163.73.101: bytes=32 time=30ms TTL=251
Reply from 66.163.73.101: bytes=32 time=29ms TTL=251
Reply from 66.163.73.101: bytes=32 time=42ms TTL=251
Reply from 66.163.73.101: bytes=32 time=30ms TTL=251
Reply from 66.163.73.101: bytes=32 time=30ms TTL=251
Reply from 66.163.73.101: bytes=32 time=42ms TTL=251
Reply from 66.163.73.101: bytes=32 time=29ms TTL=251
Reply from 66.163.73.101: bytes=32 time=41ms TTL=251
Reply from 66.163.73.101: bytes=32 time=28ms TTL=251
Reply from 66.163.73.101: bytes=32 time=27ms TTL=251
Reply from 66.163.73.101: bytes=32 time=41ms TTL=251
Request timed out.
Reply from 66.163.73.101: bytes=32 time=30ms TTL=251
Reply from 66.163.73.101: bytes=32 time=29ms TTL=251
Reply from 66.163.73.101: bytes=32 time=42ms TTL=251
Reply from 66.163.73.101: bytes=32 time=29ms TTL=251
Reply from 66.163.73.101: bytes=32 time=29ms TTL=251
Request timed out.
Reply from 66.163.73.101: bytes=32 time=28ms TTL=251
Reply from 66.163.73.101: bytes=32 time=31ms TTL=251
Reply from 66.163.73.101: bytes=32 time=42ms TTL=251
Reply from 66.163.73.101: bytes=32 time=29ms TTL=251
Reply from 66.163.73.101: bytes=32 time=42ms TTL=251
Reply from 66.163.73.101: bytes=32 time=30ms TTL=251
Reply from 66.163.73.101: bytes=32 time=31ms TTL=251
Reply from 66.163.73.101: bytes=32 time=41ms TTL=251
Reply from 66.163.73.101: bytes=32 time=41ms TTL=251
Reply from 66.163.73.101: bytes=32 time=29ms TTL=251
Reply from 66.163.73.101: bytes=32 time=26ms TTL=251
Reply from 66.163.73.101: bytes=32 time=31ms TTL=251
Reply from 66.163.73.101: bytes=32 time=30ms TTL=251
Reply from 66.163.73.101: bytes=32 time=29ms TTL=251
Reply from 66.163.73.101: bytes=32 time=41ms TTL=251
Reply from 66.163.73.101: bytes=32 time=58ms TTL=251
Reply from 66.163.73.101: bytes=32 time=29ms TTL=251
Request timed out.
Reply from 66.163.73.101: bytes=32 time=32ms TTL=251
Reply from 66.163.73.101: bytes=32 time=30ms TTL=251
Reply from 66.163.73.101: bytes=32 time=32ms TTL=251
Reply from 66.163.73.101: bytes=32 time=42ms TTL=251
Reply from 66.163.73.101: bytes=32 time=28ms TTL=251
Ping statistics for 66.163.73.101:
Packets: Sent = 43, Received = 40, Lost = 3 (6% loss),
Approximate round trip times in milli-seconds:
Minimum = 26ms, Maximum = 58ms, Average = 33ms
Control-C
************************************************** ***
C:\Documents and Settings\Ross>tracert www.hardwarecanucks.com
Tracing route to www.hardwarecanucks.com [65.61.207.162]
over a maximum of 30 hops:
1 * 27 ms 8 ms 70.76.132.1
2 14 ms 19 ms 23 ms rc2nr-ge2-3-1.wp.shawcable.net [24.244.8.194]
3 26 ms 28 ms 51 ms rc1so-pos4-0-0.cg.shawcable.net [66.163.76.193]
4 43 ms 42 ms 43 ms rc2wh-pos0-0-2-0.vc.shawcable.net [66.163.77.197]
5 80 ms 60 ms 76 ms rc2wt-pos7-0.wa.shawcable.net [66.163.76.154]
6 46 ms 47 ms 47 ms rc3wt-ge3-0-0.wa.shawcable.net [66.163.68.25]
7 46 ms 71 ms 87 ms sixpeer.in2net.com [198.32.180.27]
8 72 ms 65 ms 56 ms host-65-61-192-161.in2net.com [65.61.192.161]
9 52 ms 52 ms 54 ms 65.61.207.162
Trace complete.