I've scanned my computer using various software that i've downloaded but to delete all the infections i have to buy the software, which i can't because my computer won't let me
That's a worry.
To answer your question, yes a
clean install will get rid of the infections.
First see if you can run an online scan.
http://www.pandasoftware.com/products/activescan.htmIf you can't, see if you can carry out the following steps.
I guess you have to weigh up what is easier for you, a clean install Vs removing the infections.
Download, install & update...
CLEANUPCcleaner
ANTI SPYWAREAd-Aware
Spybot S&D
ANTI VIRUSAVG Free (Set options to 'scan all files')
ANTI TROJANEWIDO (W2k & XP)
a-squared (aČ)
Turn off System Restore if applicable. (ME & XP users)
Run Ccleaner
Run Ad-Aware
Run Spybot
Run AVG Free
Run Ewido
Run a-squared (aČ)
Re-start in Safe Mode
Re-run AVG Free
Re-start in Normal Mode
Turn on System Restore if applicable. (ME & XP users)