My verticle blinds will not rotate from open to close and vice versa. Chain just slides through round thing. Sorry for that description "round thing". I will try to post photo. I took the side piece off and tried to rotate the "round thing" manually and it won't budge. How can i fix this?

 

Often there is a horizontal shaft and a plastic sprocket/pulley that goes over the shaft. The chain rides over the sprocket so when you pull the chain it rotates the shaft. If the sprocket/pulley is spinning on the shaft then you need to replace the sprocket or somehow re-attach yours to the shaft.

 

Does it mean anything that the sprocket won't move at all? I can't rotate it manually

 

Attachment 50206

this is photo of "round thing"

 

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I don't know about repairing blinds, but from what I've read, that round thing you mention does often break, and needs to be replaced. Then the blinds also need to be restrung. I don't believe it's a DIY thing, so you'd need to get it back to where you bought it to have it repaired professionally.
You could also try calling them and they may be able to send someone out to you to fix them, but depends where you got them. If you know the manufacturer, it might be best to contact them, and they'll tell you what to do.

 

here is a photo of the sprocket that won't turn

 

Look up inside the track for anything that's broken or appears jammed. Each vertical strip has a plastic carrier. Inside each carrier are a couple plastic gears that do the rotating that can break and jam the works. As a simple fix is removing the one that's broken but it will leave a space in the vertical blinds. If you are stuck inside on a rainy weekend and really want a project you can disassemble the whole thing and move the broken carrier to the end where it's less noticeable or if the blind is longer than needed for your window you can scavenge the unused portion for parts. It can be done but it tried my patience. Unless it's a particularly expensive blind I'd be temped to just get a new one.