need help fixing error with pc, proxy error in all browsers

Question

i recently had installed a program named mask surf pro to be able to access US only sites, it worked well but i found an alternative. after uninstalling i have been getting error messages in IE and firefox saying that i cannot connect to a proxy. i can use internet by changing settings manually, but whenever i restart the program i have to repeat the process.
i need help to turn this off
p.s. i have scanned pc for virus, etc... and it is clean, so that is not an issue
thx to those who could help