Here are a few things you may want to check before taking 15 or 20 minutes to type out your problem and describe it and list the hardware you are running and describe the type of install you have done.. you may find specific information, and even fix the problem much quicker if you check these places:
(Hopefully other contributors will add to this list.. these are just some of the diagnostic tools that I can think of right now.)
Don't include the quotes.
1. Click Start and type and enter "ev" and it will run the Event Viewer. Look under Custom at the Administrative logs. Problems with initializing drivers are logged here at startup.
2. Click Start and type "Device Manager" and look for any driver errors.. usually a yellow triangle.
3. Click Start and type "perfmon /report" and press enter... it takes 60 seconds to gather a comprehensive diagnostic report and then it presents resolutions.
4. Click Start and type "Find" and you'll have a menu of about a dozen "Find and Fix" utilities. ..even more if you type "trouble" and go to the troubleshooting menu.
5. If you upgraded fro Vista, click Start and type and enter "Msconfig" and under "startup" uncheck everything... the upgrade could have carried over a ton of programs that start automatically and two tons of malware.
Appended this from my blogs:
Problem: Windows shuts down, has trouble booting under Win 7 but was ok under Vista/XP.
Solution: If I could solve even a few of the problems that cause Windows to crash I would
be wealthy and famous... but there are a few likely suspects:
1. Your power supply is inadequate... you may have added more hard drives or a power hungry
graphics card and when you install Windows 7 your PS couldn't cope. If you suspect this problem,
unplug anything you can do without that is taking power, ie, backup hard drives, extra cooling fans,
many cpu fans have speed selectors that can be set to low, USB devices etc. reboot and test.
2. Your bios needs new firmware
3. Your cmos has something misconfigured for Win 7. Look through your cmos menu for something
incorrect in the memory or perhaps it has floppy drive selected and you have no floppy disk. Google
resetting your cmos to factory default and try that.
If you find your problem you can use the search feature above, with key words.. like "USB" or whatever error message you found and maybe find a solution immediately.
I have included the solutions that have been found to many common (and some not so common) problems in my blogs. You can search the blogs above here too.
Finally, if someone here does help you resolve your problem... come back and let everyone know the solution you found so we don't have to keep "reinventing the wheel" ...and thank those who helped... you can also give them some reputation points.
Good luck.