We have one 6530b HP laptop machine with us, which has gone through half dozen formats, mainly due to issues with network adaptor. The last format was performed 2 weeks back and realized one important factor. If windows finds a proper driver for your network adaptor, NEVER NEVER try to upgrade the driver using OEM or chip manufacturer drivers!
We were doing the same mistake always as the driver configured by Microsoft dates back to year 2009 beginning. Once the driver set by Microsoft untouched, the network related issues are almost non-existing right now.
Hope this information is useful for those who have few years old hardware and a new age OS like Windows 7!