Based on some discussions I've had with SKYMTL, I'd suggest you do some heavy research WRT battery life + win7 on your particular model. There apparently is an issue upgrading to windows7 with some laptops that didn't initially ship with Win7. Best I can figure is that the power saving/battery life reporting feature of win7 writes something to the firmware of some laptop batteries which actually trashes the battery (even new replacement ones), and within a couple of weeks has their life down to something like 20% at best.
I'd personally be very leery about upgrading a laptop to win7 unless I could find definitive proof that the particular laptop doesn't have that problem.
edit: This would be a good place to start.... I know it was an eye opener when I (quickly) had a look at what SKYMTL was talking about........
windows 7 laptop battery problem - Google Search=
__________________
EVGA X58 3X SLI / i7 980X / 3X 4G Mushkin Blackline Frostbite / XFX Pro 1000W / EVGA GTX 680 SC+ 2GB / Corsair F120 / WD 6401AALS / TT Lvl 10 GT
Swiftech MCP655 WC Pump / EK XT 240 Rad / 2X Scythe Ultra Kaze / EK Supreme HF / Primochill Myriad Dual Bay Res / Dell UltraSharp U2412M
Sabertooth 990FX / PhII X4 965 / 2X4G Corsair XMS3 / EVGA GTX580 + EK Block / Corsair 120G Force GT
Corsair TX750 / XSPC EX240 / Swiftech MCP655-B / XSPC Dual Bay Res / ? CPU block / Bitfenix Ghost / Samsung 931BF