To state my issue simply, any attempt of mine to access "ask.com" will always be redirected to "http://www.search-guru.com/?from=ask". This occurs both from my URL bar and from any link that redirects to any part of ask.com. This occurs in Firefox but not Chrome; I've not attempted replicating the issue in IE.
To date, I've checked through my add-ons and extensions multiple times without spotting anything that appears to be involved. I have run scans with Norton 360, Avast!, Spybot, AntiMalwareBytes, and IObit Antimalware, but not a single program I try manages to find anything amiss. I should also state I've had this issue for months to somewhere over a year now, but I've only recently gained the sense to seek personal help, as multiple Google searches have failed to provide me with any useful information.
I believe I should also mention I've had a Spigot-based adware infection for some indeterminate time now (which I've hopefully resolved permaneantly earlier today). Due to the length of time it's been, I do not know when this issue began or if it began along with a download of some sort.
If I need to provide more technical information for anybody to ascertain the cause of this issue, then I'll likely need instructions on how to provide such information.