Computer Question.

[blackjack]

You can install then remove the same program as many times as you want, the only thing to be carefully of if is a program that when installed goes into a shared file used by another program, as deleting shared folders can end up giving you a big head ache if done wrongly, I download and install software constantly to test them then remove them sometimes less than an hour later with no problems so you will be fine, defragging the drive regular is recommended to clean up all the odds and sods that get left behind.

 

[setishock]

But above all unistall the program from add/remove programs. Deleting the file from the program folder can leave entries in the reg that take up space and xp has to keep up with. I do a lot of beta testing so I add and remove a lot of software on a regular basis.
Add/remove programs
Reg cleaner (I use nbg cleaner)
Defrag
Reboot

 

[rot13]

Defragmenting doesnt make that much a difference in the long term as I had a computer which had not had HDD maintenance in three years, defragmented it 5 times and it made no difference so I reformatted. Now its like its brand new all over again so be wary of that.

 

[srp555]

I agree with Tom Knox, how much the performance is affected by fragmentation would probably depend on the severity and also usage. For someone who doesnt use the computer for heavy tasks, they might not notice much difference. However if you are used to disk intensive applications, you will definitely feel the hit; sustained heavy fragmentation might lead to stability problems.