iPad: After changing SIM cannot get 3G connectivity

Cannot help with the issue that I am having with iPad here. Really cannot help it. I have not jailbreaked but still I get the issue with this iPad. I have to travel a lot so I have two SIM cards and I use them depending on the availability of the Signal Strength that I get. Now I was using the other SIM (The one from Vodafone) as I was not able to find the connections with the Regular SIM (H3G SIM) there. When I was getting back I have seen that it is not allowing me to use iPad with the H3G SIM. Really weird and it has happen for the first time after I upgraded iPad with iOS 4.2.1. Any suggestions.

Well it looks like that you have the setting saved for the Vodaofone SIM set in iPad and it is getting conflicted with the settings that you have made for the H3G SIM. SO it will be nice if you can Switch off the iPad again and see if this time it takes the settings for the H3G SIM. Hopefully I am of the opinion that you will be able to have the issue solved after this thing here. Try this for once and let me know if I was correct here.

Looking at the scenario it seems that the iOS 4.2.1 is the culprit here and if you had installed it after coming hope then I am sure that this can be the probable reason for the issue here. Well I am surprised that you are having no other issue apart from this with this iOS 4.2.1. I have seen most of the other users complaining that iPad is getting freeze and so on. Well if you want to have something on suggestion then let me tell you that it will be simply great if you can have this iOS uninstalled here.

You are having the issue with the connectivity then let me tell you that it will be really great if you can just have the Network Setting Reset there for the iPad of yours. Well try to do this and in addition to this see if you can go with resetting the iPad as well. It can be happening because of setting might have got disturbed and resetting the things will simply put back iPad of your with the previous stable version here. Please do this and see if this solves the issue of yours here.

No really I do not think that you will be required to take that much trouble here. Just do this: Turn of iPad and remove the H3G SIM from it. Now after this install the Vodafone SIM that you had used on the tour. Turn on the iPad and then close all the connection for Vodafone here. After this shut down the iPad and remove the Vodafone SIM from here. Install the H3G SIM and then restart iPad. Now try to see if you can get the things working or else it will be great if you can have the reset done here for sure. Please try this and let me know if this is really the thing here.

Thanks a lot for the various suggestions and let me tell you that the last post really helped me to some extent. I was really fed up and was about to make contact to the Tech Support but I just did all the things that were mentioned below and now I can have the 3G working in my iPad with full connectivity here. I was thinking of going with the RESET but the last post really helped. Regarding the iOS version let me tell you that yes it is really working great and after getting it installed this was the very first issue that I came across here.