We need quite a bit more information in order to help.
Please provide the make and model number of your PC.
Where did you purchase Windows 7 and what version and bit rate is it?
Is that a three year old PC from new or did you get it three years ago second hand?
A three year old PC is extremely unlikely to have been sold from new with XP pre-installed unless it was extremely old stock, it would have been Vista or Windows 7. Vista came out in 2007 and Windows 7 in 2009. Please tell me the history of the PC.
If your CD ROM has failed you should replace it, upgrading the OS is not likely to make any difference to that problem.
Was the problem with the CD drive or the problem with installing Windows 7 what Microsoft wanted to charge you for?
Please try to answer all the questions as best you can so we have all the facts.
Please provide the make and model number of your PC.
Where did you purchase Windows 7 and what version and bit rate is it?
Is that a three year old PC from new or did you get it three years ago second hand?
A three year old PC is extremely unlikely to have been sold from new with XP pre-installed unless it was extremely old stock, it would have been Vista or Windows 7. Vista came out in 2007 and Windows 7 in 2009. Please tell me the history of the PC.
If your CD ROM has failed you should replace it, upgrading the OS is not likely to make any difference to that problem.
Was the problem with the CD drive or the problem with installing Windows 7 what Microsoft wanted to charge you for?
Please try to answer all the questions as best you can so we have all the facts.