Reimage is pretty good, and I have used it http://www.reimageplus.com/ Read it over carefully and it ain't a 19.95 fix either.
But, I am no computer guru, yet recently ran into some issues. My discovery was two fold. I had too many windows open at the same time and heat. My heater vent is at the floor near my PC - heat, duh? And, I can't really afford the AC during 90+ days in Sunny SoCal.
I discovered my motherboard will support a quad processor. I have a duo now 3.2ghz. The quad I will be using will be slower 2.8ghz and windows won't process any faster, but I will be able to play the music and have bunches of windows open for writing - research - referencing etc. I do that much more when working on articles for HubPages.
The neat part is I have a PC that is about 5 years old. Plenty of memory, too big of a hard drive actually, just needs a little update for my needs. The processor is about $66. A lot cheaper than a windows 7 and i7 processor & mobo or new PC. I don't game.
Also check out Tuneup utilities or another utility that will help you determine what not to run in the background consuming your processor's time.
The key to remember is the computer in all actuality can only do one thing at a time - read a 0 or 1 and then respond. It's just how fast or quick
I make no bones I know very little about computing. This information is based on hearsay, 2nd hand knowledge and personal research.
Blue screens & crashes are like poor reception and naps, oddly. They are complicated rascals like kids are. TMI overloads them too like us. And, things simply wear out or as Paradigm Search points out entropy sets in. I described a solution for me = 3 more years before a new investment. Good PC shops - reiterating - GOOD PC shops really aren't expensive when viewing their intrinsic value regarding an investment. Information is powerful stuff.
Good luck and write a hub about your adventure