Welcome to Android Central! What device do you have? It would also help to know what you've tried, because otherwise, people may just assume that you've tried what they might suggest, and not bother to reply.
Things I usually suggest are:
1. Go to Settings>Apps>All, select Google Play Store, and Force Stop, then Clear Cache/Clear Data.
2. Do the same for Download Manager (and make sure Download Manager is not Disabled).
3. Remove your Google account in Settings>Accounts, then add it back again.
4. A system cache partition wipe (if possible on your device).
If all else fails, try a factory data reset.
11-22-2014 01:19 AM