You should only update the BIOS if there is a problem. Otherwise, leave it alone. BTW, Dell usually does a very thorough job of testing BIOS updates before they are made available so updating is not an issue.
I mean uncompatibilty with windows 7.... As i want it....
Does this heat up during games?
Does any driver cd came along with it or we have to download frm there site?
All you would need to do then is disable Secure Boot in the BIOS. Not an issue.
You can purchase a drivers CD/DVD with Dells, and some already include them. Of course, you can always download all of the latest versions at their website.
As far as heating up, all systems generate more heat when put under load (like when gaming).