Naujzerep welcome to Avast! forums
It means that some services that Avast needs to work properly are stopped. Also some other program like the old AV you had may be involved.
If you feel more comfortable in Spanish, there is a Spanish forum here:
http://forum.avast.com/index.php?board=25.0
Where I can give you instructions to resolve the problem, Otherwise you may follow this guide:
Install from scratch:
1.) Very important to remove all remains of other AVs installed before Avast. Use this site to execute uninstall utilities for other AVs.
http://singularlabs.com/uninstallers/security-software/
2.) Download and save to your desktop aswclear.exe
3.) Download and save a fresh copy of Avast!. Be sure to have your lincense handy if running a paid version.
http://files.avast.com/iavs5x/avast_free_antivirus_setup.exe
http://files.avast.com/iavs5x/avast_pro_antivirus_setup.exe
http://files.avast.com/iavs5x/avast_internet_security_setup.exe
4.) Open Avast! > Settings > Troubleshooting > Untick " Enable Avast! self-defense module ".
5.) Uninstall Avast! normally through Control Panel > Programs & feature ( Vista, W7 ) or Add and remove programs ( XP ). Reboot. If you can not complete this step, continue with step # 6
6.) Even if you were able to uninstall Avast! in step # 5, it is important to run aswclear.exe in safe mode for any Avast! you may have had before and then for v. 7. Reboot into normal mode after uninstall.
https://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=1062#idt_02
7.) Reinstall fresh copy of Avast! and reboot.
Be aware. Avast! will offer Chrome during installment. Remember to opt-out if you do not want it.