If u r able to install uninstall s/w, then try this.
1> First and foremost back-up important data. (U know, if u required to format...)
2> Download RemoveITPro from
here. Its freware and very good in scanning. Try it u won't regret.
3> QuickHeal and Avast both of them has option for BootTime scanning, go for it.
4> Adware. Install and do a full scan.
For all those s/w first update and then SCAN,
while scanning remember to be in offline mode.
Report ur result here.