Car won't accelerate, but rpms increase?

I replace my alternator on Saturday and starting that same day my car has had problems accelerating. When I hit 10mph, the rpms shoot to 4000 and I have to ease off the gas pedal. Occasionally this is accompanied by a groaning noise. I made sure that the connections to the alternator were secure, but I'm not sure what the problem could be.

The car is a 1997 Ford Taurus. I would really appreciate any advice.

Nothing to do with the alternator.

You did not say if automatic or manual, and it really makes a huge difference.
If it is an automatic, about all you can do is check the ATF level.
But generally automatics work until they need a total rebuild for about $2000.
If it is a manual, then check the clutch adjustment.
If the adjustment has enough freeplay, then the clutch is likely shot and will cost about $500.

It's called the transmission. It causes the gears to shift. When it revs, this little gear (you hear it as shifting) catches another little gear and that's what causes it to shift. If it's not catching your looking at about a $3000 repair.

Sounds like your car isn't shifting gears and is stuck in first gear. Does your car have an automatic transmission?

Check your transmission fluid. If its burnt, rather than bright red. Drain & refill. You may be able to save it. But it sounds like its ran low… Follow ford instruction on checking level. I believe its at idle, warm, in park or neutral. Always check on level ground. I would change fluid As soon as possible"

Hi so the clutch has died time to get it to a dealer or call the tow truck out.

As you said your car will not accelerate when the gas pedal is pressed down then the question becomes is it a manual transmission or an automatic? If a manual then the clutch is slipping under load and needs to be replaced. If it is an automatic transmission then it is low trans fluid or the clutches have burnt. If its low oil level fill it to the full mark and no more. Otherwise its time for a trans rebuild.