Im a Pc dummie, Please HELP!!!!!

Hello,

Ive been renting a Dell Pc for the last few mths. Its windows Xp and i only use it for basic things ie Ebay and Email. Im virtually a beginner and im rubbish with computers!!

Long story short, ive had problem after problem with this Pc and everytime i report a problem with the man that i rent the Pc from, he charges a call out fee, a fee to repair the computer plus extras for parts etc. I cant afford to call him out again and i have to stick with this company as im a single parent and to buy a Pc outright, is just not in my budget unfortunately.. I feel that im basically paying my mthly talktalk bill for nothing whilst i cannot use my computer!

This is the problem.... unbeknown to me, my 2 year old daughter was playing with my Pc. As far as i can tell, she has deleted various programmes. I think one of these may have been my windows Xp.
When i turn the Pc on, i can still enter my username and password. However, i get a pop up message telling me that my screen resolution is too high..? Basically (in my words,) the screens colours are blurry and i cannot adjust this in my control panel like many sites have suggested!
I cannot see any of the pictures stored in my albums, i cannot see my screen properly and as my Pc is rented, i dont have an Xp installation disk (which is what most sites say that i need!!!)
Ive tried re-setting the Pc to how it was a few days ago, (though i havent a clue how i did it now) and it made no difference!
Last but not least, the Pc keeps crashing and saying the following... 'microsoft has encountered a problem. Send error report/Dont send error report'

Any help or advice that anyone can give me, i would really appreciate.

Thanks Jo