I was trying to download pdf convertor , now my computer is corrupted , can not open the web browser.
Talked to the tech person and advised to reformat. I have particular programs ( spss and quickbook pro)  need to  be saved because  I do not have the cd. Is there any advise to save them before I format my computer? 

installed programs can be copied into flashdrive or other media
go to the partition that has your softwares installed on it (usually drive C); open the folder called program files.
if you have windows 7, there will be two folders : program files and program files (x86) or something like that. check both folders, copy the folder that has name of the software of your interest.
after you're done with fixing your computer, copy/paste  those folders back into their original place

FYI: this might not work and there's no other solution that i know of.
but if you have the installation file (the one you downloaded; usually they have .exe extension. like firefox.exe) copy that to external device and you'll be able to install it later.

 you can only copy those installed software which do not have any registry entry. Otherwise copying won't help. 

 find serial numbers of the programs alaready installed. Copy those and re install when you re format. Here is some instructions. http://www.makeuseof.com/tag/3-ways-recover-serial-numbers-windows/

 here is another article on it. http://pcsupport.about.com/od/productkeysactivation/tp/topkeyfinder.htm

If browser is the only problem ,you can try to reset the browser back to default.
Otherwise, as folks mentioned early, you will need to find your serial number.

Try restoring to your sytem to an earlier date (before you downloaded and installed the PDF converter)

Thank you all,
Lesson learn from downloading free software. It does not let me restore anyting nor it let's me to run security essential. I ran malware software and it says nothing found.
I will use the recovery system but do I have to format C drive, then how to do it? It formats automatically or gives choice? Running on window 7 32 bit .