Windows XP is corrupted

Hi,I am hoping someone can help
my husband has deleted files/registry he shouldn't have using some registry program.He says he did a scan and just pressed delete and he has inadvertently destroyed his XP computer.
I have tried to fix it without success.It is a OEM PC and it was on its last legs a few months ago and it took several attempts to accept a fresh install of XP so i really want if possible to avoid doing that this time.

The desktop icons have lost their pictures and wont open locations,pressing them just makes useless short cut icons.

It says i have to create option in folder options but this does nothing!

System restore is gone as is menu from 'start'!
I cannot access recycle bin as i thought the deleted files may be there but i cannot access them.

I tried safe mode to go back to last know configuration but this did nothing!

I thought (but i may be wrong) that pressing F9 on start up would let me put pc into non destructive recovery but it didn't and we have had trouble with this in the past anyhow.

Can anyone help?
Thankyou
Lisa

 

Thanks Tim but you need a start up cd to initiate this and i do not have one.
I installed XP last time using someone elses copy but my own serial number but my pc refused it numerous times and it was touch and go.
Thankyou for your help
Lisa