Definitely back up your important files before trying any fixes. I learned this the hard way when I lost 3 years of photos trying to fix a simple problem. Get an external hard drive or burn DVDs of your important stuff first.

Don't forget about heat. If your computer is shutting down or crashing randomly, open the case and check if the fans are caked with dust. Blow it out with a can of compressed air. Overheating causes a shocking number of 'mystery' problems.

I always tell people: buy a UPS battery backup. A $40 one will protect your PC from power surges and brownouts that slowly kill your hardware. Lost a motherboard to a thunderstorm once. Never again.

Newegg is your friend for parts. Way cheaper than Best Buy or CompUSA and the customer reviews actually help you avoid junk. Just watch out for shipping on heavy stuff like CRT monitors. Read the reviews before you buy ANYTHING.

I'd post this on the Tom's Hardware or AnandTech forums with your full system specs — CPU, RAM, motherboard, the works. People can't really help without knowing what you've got. The more detail you give, the better the answers.

This is a case where spending a little more upfront saves you money in the long run. Cheap hardware fails faster and costs more to replace. Buy quality components from reputable brands and they'll last years longer.

I'd recommend trying the free solution first before spending money. Nine times out of ten, the free option works just as well as the paid one. Only upgrade to paid software if the free version doesn't meet your needs.