Internet Connectivity Problem

Hello,
I am at university and internet connection is provided through a proxy server.The computers are connected through LAN.I tried to install Comodo Firewall Pro v3.0.21.329,but the setup window had disappeared after some time.When I restarted the system and went to Program Files,I found the CFP.exe file in the Comodo folder.I opened it and it asked me to run the diagnostics tools.It repaired the installation and internet worked for some time(not properly).When internet stopped working I tried to uninstall it but couldn't find the uninstall option.So I deleted the comodo folder,but it couldn't be completely deleted completely.I installed it again properly but internet didn't work.I found the uninstall option from the start menu and uninstalled it.Then I learnt that there was some repair going on in the institute network.So I waited but even after the repair internet didn't work.I tried system restore thrice but it failed.Then I did system restore in Safe Mode but the required restore point was deleted.I restored to the configuration(oldest) in which it was partially installed.I installed Comodo to get the uninstall option and uninstalled it.Then I read about netsh winsock reset and netsh int ip reset commands.I tried both and when I restart the computer and configure the TCP/IPv4 settings in the LAN properties,internet starts working.But I have to use the netsh int ip reset command everytime before shutdown and the next time reconfigre the settings for internet to work.When I run the netsh int ip reset command as administrator,the system returns
Reseting Echo Request,failed.
Access is denied.
Reseting Global, OK!
Reseting Interface, OK!
Reseting Unicast Address, OK!
Reseting Route, OK!
A reboot is required to complete this action.
I use cntlm for proxy authentication as many programs won't work without proxy authenticaion.My operating system is Windows Vista Home Basic 32 bit.Is reseting the TCP/IP stack many times harmful for the computer? Should I disable the network adapter or unplug the network cable before the reseting process.Please help.
Thank You!