phone scam

What do I need to do after I let someone get in my computer with team viewer?

Are you having problems with your PC? What if any security scans have you run, and did they detect/remove anything?

Why did you install TeamViewer? If it was because you received an unsolicited phone call claiming that your computer had malware or needing fixing, then yes it almost certainly was a scam.

TeamViewer itself is a legitimate program, and safe when used between trusted parties. TeamViewer can generally be uninstalled from the Control Panel>Programs and Features (Windows 7 & 8).

If you actually used TeamViewer to allow remote access and control of your computer to a scammer, then you might well be in trouble - anything from identity theft, banking, credit card, or other financial fraud, installation of malware, keyloggers to discover PINs and Passwords, and other cybercrimes. The list goes on.

If all you did was install TeamViewer, but never activated or configured it for internet access, then probably all you need to do is uninstall the program manually as noted above.

If you suspect you might have given remote access to your system to an unknown party, I would suggest at a minimum that you:
1) Check your bank and credit card accounts ASAP for suspicious activity or withdrawals. Notify financial institutions at once of anything suspicious. You might end up having to cancel credit cards, and change PINs and Passwords for financial sites.
2) Stay offline, and avoid internet financial transactions until you have assurances you are not at risk.
3) Run a good anti-malware scan. I recommend Malwarebytes Anti-Malware (MBAM). The free version will remove detected malware. You can download it here: http://www.malwarebytes.org/
4) If you still have significant problems with your computer or browser, be advised that malware removal and analysis is no longer done here in Dell's forums. We can direct you to forums dedicated to malware removal, staffed by experts, and at no cost.

Let us know how it goes. Good luck!