Can i hookup 2 monitors,2 keyboards and 2 mouse to 1 computer?

The only way to share an office computer with your shop area is to have something in the shop (a computer or terminal like those made by Wyse) that can connect back to the office PC. This does not solve your problem. Depending on the distance from shop to office, you could house the second PC in the office and use extension cables to allow only the monitor, keyboard, and mouse to sit in the shop area. Your best bet (I know this is not what you want to hear) is to replace the damaged hardware and be dilligent about cleaning it in the future. As an automotive shop, I assume you have an air compressor or tank. Use this to blow dust out of the PC on a weekly basis. This will go a long way towards keeping it running.

For the second monitor you'll need a second video card [already there if using a notebook computer] and the keyboard and mouse should easily plug into your USB ports. May need a USB hub to make space. Think of it this way, dual monitors are commonly used. Anytime you plug a mouse into a laptop/notebook you have 2 mice [touch pad and external mouse] and the same applies for adding a wireless keyboard to your laptop. On a desktop you'll need to ad a second video card..

Answer is yes using either splitters or usb or wireless mouse/keyboard. The issue here is going to be how long do you need the cables. Most monitor cables are only good for a max of around 25 feet. Keyboard and mouse cables even shorter. Also finding the longer cables may be hard and expensive.

That should work I believe...just get splitters for each, VGA splitter for the monitor and PS/2 splitters for the keyboards and mice.

The solutions I see above are not very practical. Yes, you could manage to fix up dual inputs and outputs. You would have problems finding cables long enough, and probably would have noise immunity issues. Two people would not be able to use the one computer at the same time - you just have dual controls for the one computer. People make computers for dirty industrial environments. They tend to run fairly expensive. Last time I looked they were about 2x home computers. All you need to do is to keep the dust and grime from inside your computer. One way would be to vent and blow outside air into the computer fan intake, enough to create a positive pressure inside the computer. Another way would be to put the second computer in a filtered-air enclosure. A third way would be to place the computer on the other side of a shop wall.

If you have a dual output VGA card and use USB keyboards & mice you should be good to go.