-try to bring up msconfig. If it does not show up, its a worm or a trojan. If it does show up, clear up all non-essential items from the startup.
-does the comp freeze when you use particular programs? does it happen at a particular level of CPU use? This could be an overheating problem. Open up your cabinet and check if the fan has collected dust.
-Some processes run automatically at certain times. ISP providers launch ads at intervals on IE, for example. Check if the browser launching is causing the freeze. Also check autoupdate features in any AV/OS that you use. If this is the problem, disable auto-update and IE.
-Open your cabinet, and check for loose contacts. If your RAM has slipped, your comp won't start at all, but check the hard disk connections, and the drive connections. See if there is anything loose.
-Also check if any of the wiring is interfering with the fan.
-If none of these help, it is almost certainly a problem with the operating system files. Drivers should not freeze, unless the system is detecting a new hardware, and taking a long time over that. If you have recently connected a new Hard Drive, web cam, printer, scanner - etc, then disconnect this and check.
-Bring up the task manager, and have a look at the processes. Check out suspicious processes on this site.. This will help you identify and trojans/spyware/viruses/worms that might be hogging your resources.
-Run a boot time scan. If you don't have an antivirus that does this, use Avast from the Nov DVD.
