My employer just cut my salary by 25% and stopped all health benefits. I do not want to work for this, can I collect full-time unemployment if i quit
Probably not. Some states do recognize the concept of "constructive termination," in which working conditions are changed so negatively that no one would work for them and therefore a person could be considered to have been fired (forced out) by the conditions. However, it is not clear that a pay cut like this would qualify, especially during a recession when 1 in 8 adult who want to work are unemployed and many people have taken paycuts or unpaid leave. It might be considered that even a paycut like this is not enough to constructively terminate someone and that in these conditions, people should not quit over pay or benefit reductions. (Usually, constructive termination applies to being forced to work night shifts when you'd been hired for day, or relocated to a distant location with an unreasonable commute.)
It is probably better to keep working, doing the minimum to keep your job, while looking for a new job.