Isn't it the drunk guy on the bench?
showquesttargets
this command lists all your current/active quests (by 'id' so look them up on uesp or elsewhere to find out which is which, some are 'obvious' from the initials, some not).
sqs <questid>
this lists all the stages and a 1 if the stage is complete and a 0 if it is not, so you can 'step through' stages from your current position to a later one (better than leapfrogging multiple stages at once)
So if you do "sqs mq201" it should give you a short numeric table of stages and their status of completedness, see if that helps you find the correct value(s). You could also try a "resetquest mq201" and then advancing the stages back up from the beginning to see if it fixes any holes in your current progression of the quest.
I suggest never using these commands without first doing a proper save of the game; it is possible to bug yourself even more when using them incorrectly.
I was doing the Companion's quests and on one of them a guy would be my follower, on that quest. Since then Lydia stoped following me, and now I can't find her.
Using Steam launch options to install retail games from disc
Log in to Steam and click on Library.
Right-click on the game, select Delete local content, and confirm.
Insert the first disc into your computer.
Close Steam (Steam > Exit).
Press Windows Key + R to open Run
In the Run window type: "C:\Program Files\Steam\Steam.exe" -install E:
Replace E: with the CD/DVD drive you are installing from if is not correct. Replace C:\Program Files\Steam if your Steam installation is not in the default location. Press OK. Steam will launch and ask you to sign in if you do not have your password saved. Your installation should continue from the disc.
Have you checked your house in Whiterun? She should be in there.