msconfig access denied error

I got some issues installing software for a new HP printer/scanner so called their tech support for help. They told me to delete many registry entries. After that many problems started to arise from that period, some of those I was able to correct, but one of the remaining issues is that when I use msconfig to change startup settings then I get a message that says "An
access denied error occurred. You may need to log on using an administrator account." I am working on Windows XP SP2 and if anyone has some solution then please let me know.

Even I am facing this issue when going into msconfig that is denying me access asking for administrator. I am already the admin when I go into administrator in safe mode then same things happens. I want to solve this issue.

You should carefully use Registry editor. You should also be certain for whatever things you change and copy the registry first so you can revet back to the previous one without any issues.

I had a similar problem. the issues were
a) restarting the system when msconfig was changed and not deleting the registry entry
b) ALso trojanware that inserted entries back in msconfig-> startup
see my complete solution on my blog.

I had a similar problem with HP 6310 officejet multifunction. Thankfully, I followed some threads and found a patch and a security update on the HP website. I downloaded/installed and rebooted and voila, the problem was fixed.