Is The Answer to Re-install Over Itself?

I am having a number of minor but niggling problems with my computer like
1 After installing the latest update of Nokia Ovi Suite I can no longer connect my Nokia phone to my computer as Nokia Ovi Suite will not, or cannot, install the drivers.

2 My web browsing is sometimes quite slow.

I have tried: deleting Temporary Internet Files; running CCleaner; running Anti Malware software; running sfc /scannow and booting from my Windows repair disk but without success.

It may be that I have, or some Windows update has, corrupted some system files.

My question is this, is it possible to repair any files that may have been corrupted by re-installing Windows 7 over itself?

Any views or comments would be most welcome.

My computer specs are as follows:

Motherboard Name ASRock K10N78D
Operating System Microsoft Windows 7 Ultimate N 6.1.7600 (Win7 RTM) 64bit
CPU Type AMD Phenom II X2 Black Edition 550 (DualCore), 3100 MHz
System Memory 6GB (DDR2-800 DDR2 SDRAM)
Video Adapter NVIDIA GeForce GT 220 (1024 MB)
Hard Disk 2 x Hitachi Deskstar 500Gb
Internet Explorer 8.0.7600.16385
Antivirus AVG Freeware
Firewall Windows own

Yes, an Upgrade over itself is the Repair Install in Win7: http://www.sevenforums.com/tutorials/3413-repair-install.html?ltr=R

First I'd run http://www.sevenforums.com/tutorials/1538-sfc-scannow-command-system-file-checker.html to check the System File integrity.

Also download, install and Update Malwarebytes to run a Full Scan. Malwarebytes

Win7 troubleshooting fundamentals

If these don't resolve the issue, consider wiping the HD of all (corrupted, infected) code and clean reinstalling Win7 using these tips to get a purrfect reinstall: http://www.sevenforums.com/installation-setup/125874-re-install-windows-7-a.html#post1086729