Windows 7: Help please - windows installer

I just got a computer which has windows7 on it.
I then tried to load on the applications i needed.
NOw my windows installer has died , giving me the error '1719'
I tried a whole heap of reg cleaners and none seem to make a difference.
My windows installer has screwed up.
I have microsoft office 2007 , academic version, on there at the moment.

if in the end i have to restore my pc back to the factory defaults, will i lose one of my licenses???the academic version comes with one license to be used 3 times.
anybody??

You won't lose one of the licenses and reg cleaners are a very bad idea. I have never seem them cause anything but trouble. I used one once when I was 15 (over 4 years ago). I had to reinstall from scratch and I lost a lot of files I still consider to have been important (. Many people on here will tell you similar stories caused by them. I would definitely do the restore at this point.

Also, when similar problems occur in the future you can just do a system restore.
System Restore

what about activating the licencse??? would the previous install that ha been removed count as one use??

Same computer, so no. I can't think of a single reason why it would be. The general rule is, some motherboard, same computer.